FR2908255A1 - ALLOCATION OF FREQUENCY BANDS TO RADIO COMMUNICATION SYSTEMS - Google Patents

Abstract

To allocate frequency bands to radio systems, a frequency band allocation to each system is modeled (E2) by a three-dimensional block based on a frequency bandwidth and a coverage area of the frequency band. system to determine modeled block distributions. A score is assigned (E5) to each distribution based on a minimum frequency band including all the frequency bands of the blocks of the distribution. Frequency bands are allocated to the systems according to an adopted distribution (E10) having a score greater than a threshold. The score assigned may depend on a number of collisions between blocks of the distribution and protection bubbles constructed (E4) around of modeled blocks in which the systems do not experience mutual interference beyond the respective tolerance thresholds.

Description

1 Frequency band allocation to radiocommunication systems

  The present invention relates to allocation of frequency bands to radio communication systems, such as cellular radio networks or wireless local area networks.

  Generally, frequency bands are allocated to radio systems in a fixed manner, in order to limit interference between the different radiocommunication systems. Frequency bands can also be dynamically allocated to radio systems, depending on space and / or time. For example, a frequency band allocation is dynamically adapted to the changing spectrum requirements of a radio system covering an agglomeration that requires a wider frequency band at the end of the week than at the beginning of the week. Some radiocommunication systems may use frequencies that vary in one or more frequency bands, so as not to cause interference within the same radio system, or to other radio systems that share one or more common frequency bands. However, it is difficult to predict interference between any two radio systems whose spectrum requirements may vary. In the state of the art, there is no general method for statically or dynamically allocating frequency bands to any number of radio communication systems in order to ensure a minimum of interference between the radiocommunication systems .

To overcome these drawbacks, a method according to the invention for allocating frequency bands respectively to radio communication systems, is characterized in that it comprises: modeling a frequency band allocation at each radiocommunication system by at least one three-dimensional block as a function of a frequency bandwidth and a coverage area of the radiocommunication system, a determination of at least one distribution of the modeled blocks, an allocation of a first score at each block distribution according to a minimum frequency band including all the frequency bands of the blocks of the distribution, and an adoption of a block distribution having a first score greater than a threshold in order to allocate frequency bands to radiocommunication systems according to the distribution adopted.

Throughout the application, coverage area is defined as an area within which a given service associated with a radiocommunication system is accessible. The invention takes into account any number of radio communication systems of any type when modeling tri-dimensional block frequency band allocations. The frequency bands are allocated according to the invention to the radiocommunication systems so as to respect the total frequency band 2908255 available for the radio communication systems, and in particular to minimize the total frequency band allocated to the radiocommunication systems. According to another characteristic of the invention, the method may furthermore comprise, around modeled blocks of each block distribution, a construction of protection bubbles in which the radiocommunication systems are able not to undergo mutual interference beyond respective tolerance thresholds, the first score being assigned to each block distribution in addition to a number of collisions between protection bubbles and distribution blocks. According to another characteristic of the invention, the method may furthermore comprise, around modeled blocks of each block distribution, a construction of protection bubbles in which the radiocommunication systems are able not to undergo mutual interference beyond respective tolerance thresholds, a second score being assigned to each block distribution based on a number of collisions between protection bubbles and distribution blocks, and a block distribution having first and second upper scores. at respective thresholds being adopted. The invention adapts the frequency band allocations dynamically to the needs of the radio systems, and so as to meet tolerance thresholds on interference between the radio systems. According to another characteristic of the invention, each protection bubble may be constructed around one block with respect to another block depending on the spatial coordinates of the coverage areas associated with the two blocks and the propagation characteristics of the two blocks respectively. radio systems associated with both blocks.

Two radiocommunication systems respectively associated with two blocks do not interfere with one another beyond the respective tolerance thresholds when the protection bubble around one block is disjoint from the other block. With shielding bubbles around the model blocks, the invention optimally allocates frequency bands to the radio systems associated with the blocks to limit interference between the radio systems.

According to another characteristic of the invention, the method according to the invention may furthermore comprise, if no block distribution has a score greater than the predetermined threshold, a selection of block distributions having the highest scores, a replacement of the unselected distributions by distributions selected so as to maintain the same number of distributions, and a random selection of at least one block distribution and at least one block of the selected distribution to change the position of the block selected according to the frequency. The method according to the invention may also comprise a random selection of two distributions and at least one radio communication system, and an inversion of the blocks associated with each selected radio communication system between the two selected distributions. Construction of the protection bubbles, scoring and selections can be iterative. As a result of the iterations, the method according to the invention determines an optimum block distribution which in particular has a minimum of interference between the radio systems and a total frequency band allocated to the radiocommunication systems which is minimal. The invention also relates to a device for allocating frequency bands respectively to 10 radio communication systems, characterized in that it comprises: - a means for modeling an allocation of a frequency band to each radiocommunication system by at least a three-dimensional block as a function of a frequency bandwidth and a coverage area of the radiocommunication system; - a means for determining at least one distribution of the modeled blocks; 20 - a means for assigning a first score to each block distribution according to a minimum frequency band including all the frequency bands of the distribution blocks, and - means for adopting a block distribution having a first score greater than a threshold in order to allocate bands of frequency to radiocommunication systems according to the distribution adopted. The invention also relates to a computer program capable of being implemented in a device for allocating frequency bands respectively to radio communication systems, said program comprising instructions which, when the program is executed in the said 2908255 6 device, perform the steps according to the method of the invention. Other features and advantages of the present invention will appear more clearly on reading the following description of several embodiments of the invention given as non-limiting examples, with reference to the corresponding appended drawings in which: FIG. 1 is a schematic block diagram of a frequency band allocation device according to the invention; FIG. 2 is a graph showing a variation of a separation between two frequency bands used respectively by two radio communication systems as a function of a distance between the coverage areas of the two radiocommunication systems; FIG. 3 is a three-dimensional space diagram showing frequency band allocation modeling to radiocommunication systems by blocks delimited by coverage areas of the respective radiocommunication systems; and FIG. 4 is an algorithm of a frequency band allocation method according to the invention. With reference to FIG. 1, the frequency band allocation device DAB according to the invention mainly comprises a central unit UC, a modeling module MOD, an evaluation module EVA, a simulation module SIM and a base BD data. The frequency band allocation method 35 according to the invention is implemented for example in the form of software implemented in the DAB frequency band allocation device, such as a personal computer or a personal computer. application server. The DAB device contains the database BD 5 including data relating to radio communication systems, such as frequency bandwidths required for antennas of radio networks and associated with the identification of the antennas and characteristics. propagation and antenna positions and dimensional characteristics of antenna coverage areas. In a variant, the database BD is in a database server connected to the DAB device locally or remotely through a telecommunications network of the Internet type. The DAB device may communicate with entities of the fixed network of at least one UMTS 20 ("Universal Mobile Telecommunications System") or GSM ("Global System for Mobile Communications") backbone network. to a GPRS network ("General Packet Radio Service"). The entities may be a maintenance center OMC 25 ("Operation and Maintenance Center" in English) and terrestrial interfaces between RNC ("Radio Network Controller") base station controllers for a UMTS type network so that the DAB device quickly transmits them lists of frequency band allocations according to the invention. For example, the cellular radio network is CDMA (Code Division Multiple Access) multiple access. In other examples, the cellular network is WCDMA broadband code access multiple access (WCDMA) or has HSPDA high speed downlink shared transport channels (High). Speed Downlink Packet Access (in English). The DAB device may also communicate with service entities of a wireless local area network of the WIFI type ("Wireless Fidelity" in English), WIMAX ("World Wide Interoperability Microwave Access" in English) or WIBRO ("Wireless Broadland"). "in English), or a proximity network of the infrared or Bluetooth type. In general, the DAB device is connected with at least two service entities each managing a radio communication system offering, for example, a fixed service, a mobile service or a broadcasting service. A radio communication system may be restricted to a base station in a radio network to which a frequency is to be allocated, or comprise a set of base stations belonging to the same radio network to which a frequency band is to be allocated. . In the latter case, the operator of the radio network can allocate itself to each base station of said set a frequency of the allocated frequency band. According to another variant, a radio communication system may be a radio communication network to which a frequency band is to be allocated. FIG. 2 is a graph showing variations of a gap Af between frequency bands respectively used by two radio communication systems as a function of the distance Ad between areas respectively covered by the two radiocommunication systems. The distance Ad and the gap Af also called "guardband" 5 depend on the radio systems concerned and are respectively less than a predetermined maximum distance AdM and a predetermined maximum deviation AfM. The two radiocommunication systems 10 do not interfere with each other if they respectively use sufficiently separated frequency bands as a function of the distance between the coverage areas of the radiocommunication systems. In particular, the two radiocommunication systems 15 do not interfere mutually if they respectively use frequency bands separated by at least the maximum frequency deviation AfM, or if the distance between the coverage areas relating to the radiocommunication systems is greater than the maximum distance AdM. In general, each pair of two radio systems is associated with an Af (Ad) graph which is different from the graphs associated with other pairs of radio systems and which depends on the propagation characteristics of the radio systems composing the pair. FIG. 3 illustrates a three-dimensional block frequency band allocation modeling in a reference frame (Ox, Oy, Of). The dimensions and contours of coverage areas of radiocommunication systems are defined using spatial coordinates x and y along two horizontal axes in a terrestrial plane of 35 coordinates. The third coordinate f along a vertical axis is used to define frequency bands to be allocated to the radiocommunication systems. An allocation of a frequency band to a radio communication system is modeled by the modeling module M0D of the DAB frequency band allocation device. The allocation of a frequency band to a radiocommunication system is represented by a block which is a three-dimensional object in FIG. 3. In an example illustrated in FIG. 3, three three-dimensional blocks BL1, BL2 and BL3 are represented and respectively associated with three different radio systems. The orthogonal projection of a block associated with a terrestrial radiocommunication system Ox, Oy corresponds to a coverage area ZC of the radiocommunication system. The orthogonal projection of the block on the vertical axis f corresponds to a frequency band (fm, fM) to be allocated to the radiocommunication system 20. For a given coverage area ZC1, several frequency bands may be allocated to a radio system. In this case, several blocks associated with the same radio system are juxtaposed parallel to the axis Of. The shape of the base of a block depends on the radio system associated with the block. For example, if the radio system is an omnidirectional antenna, the base is in the form of a disk. If the radiocommunication system is a directional antenna, the base has a circular sector shape. The MOD modeling module determines a BP1 protection bubble around a block, which illustrates the frequency compatibility limit between the radio system associated with the block and another radio communication system. The shape of a bubble is defined for a first radio system with respect to a second radio system. The bubble defines a region in which the first and second radiocommunication systems are capable of not interfering with each other beyond respective tolerance thresholds. The shape of the protection bubble BP1 is constructed by applying the curve shown in Figure 2 to block BL1. The block BL1 is enlarged laterally parallel to the terrestrial plane Ox, Oy of the maximum distance AdM for Af = 0 and vertically parallel to the frequency axis of the maximum deviation AfM for Ad = 0. At the edges of the block BL1 the frequency band (fm, fM) is enhanced by the variation of the difference Af as a function of the variation of the distance Ad embodying the two coordinates x and y in the coverage area ZC1 according to the curve illustrated in FIG. 2 to completely define the BP1 three-dimensional bubble. For example in FIG. 3, if the protection bubble BP1 around the block BL1 is disjoint from the block BL2, then the two radiocommunication systems respectively associated with the blocks BL1 and BL2 can coexist. If the frequency band allocation modeling takes into account more than two radio communication systems, at least two protection bubbles are determined around a block. For example, if the three radiocommunication systems respectively associated with the three blocks BL1, BL2 and BL3 are considered for the frequency band allocation, then two protection bubbles are determined around block BL1. A first protection bubble of block BL1 with respect to block BL2 is deduced from a first graph Af (Ad) associated with a pair of radiocommunication systems having propagation characteristics similar to those represented by blocks BL1 and BL2, respectively. A second protection bubble of block BL1 with respect to block BL3 is deduced from a second graph Af (Ad) associated with a pair of radiocommunication systems having propagation characteristics similar to those represented by blocks BL1 and BL3, respectively. By way of example, a single protection bubble BP1 around block BL1 with respect to one of blocks BL2 and BL3 is shown in FIG. 3. Referring to FIG. The frequency according to the invention comprises steps E1 to E10 executed under the control of the central processing unit UC in the frequency band allocation device DAB. In step E1, the frequency band allocation device DAB collects information relating to coverage area mappings for each radio communication system whose operator wishes to benefit from a frequency band allocation. In addition, the DAB device is informed of the spectrum requirements for each radio system, i.e., the frequency bandwidth required by each radio system. For each radiocommunication system, the collected information includes the spatial coordinates of the radio system coverage area ZC, as well as the frequency bandwidth required by the radio system, and is stored in the base station of the radio system. BD data. At a given point in the terrestrial plane, several radiocommunication systems can coexist. Indeed, a base station may comprise several antennas each requiring a frequency bandwidth in a different frequency band. For example, one antenna requires a frequency bandwidth in a UMTS-type specific frequency band and another antenna requires a frequency bandwidth in a WIMAX-type specific frequency band. In step E2, the modeling module MOD analyzes the information stored in the database BD and models, for each radio system, an allocation of a frequency band (fm, fM) to the radiocommunication system by a three-dimensional block BL as a function of the frequency bandwidth fM-fm required by the radiocommunication system and the size and position of the coverage area ZC of the radiocommunication system. The width of the frequency band to be allocated to a radiocommunication system is then at least equal to the frequency bandwidth required by the radiocommunication system. In step E3, the modeling module MOD determines one or more EPR distributions of the BL model blocks as a function of the variation of the limits fm and fM of the frequency bands to be allocated which depend on the required frequency band widths fM-fm 2908255 14 not the radio systems associated with the blocks. Each REP distribution contains at least as many blocks as there are radiocommunication systems. For each radio system, the model block BL having a height equal to the frequency bandwidth fM - fm required by the radio communication system has positions in the frame (Ox, Oy, Of) which can vary only according to the The frequency axis Of and which are associated with the PWR distributions, a position of the block that can be associated with several PWR distributions. For example, for each distribution of REP blocks, the blocks are randomly placed relative to each other along the frequency axis Of. In a particular case, the block distributions are determined in such a way that no block covers another block and that all the frequency bands to be allocated to the radio systems associated with the blocks are contained in a predetermined total frequency band. In another example, one or more block distributions contain at least two blocks that are not disjoint. For example, the MOD modeling module determines a set of R = 50 block distributions to be optimized in the following steps. The following steps E4 to E9 are performed iteratively by the DAB frequency band allocation device to determine an optimum block distribution satisfying predetermined criteria depending on evaluated magnitudes.

At an initial iteration 0, the modeling module MOD constructs BP protection bubbles around blocks BL among the blocks modeled for each distribution of REP blocks, in step E4. Each bubble of protection around a first block is constructed with respect to a second block as a function of the Af (Ad) graph associated with a pair of radiocommunication systems having similar propagation characteristics respectively to the systems represented by the first and second second blocks. For example, for each block, the modeling module MOD determines as many protection bubbles around the block as blocks modeled except the block considered. Thus, one block is surrounded by a protection bubble with respect to another block. In another example, for two radio systems considered, a single bubble of protection is determined around one of the two blocks. In this case, for N considered radio systems, a number NB of bubbles to be determined around blocks of index i is given by the following relation: NB = N (N - 1) / 2.

Alternatively, when two blocks are separated by a greater distance than a predetermined distance, no protection bubble is determined around one of the blocks.

In step E5, the EVA evaluation module assigns at least one SC score to each REP block distribution. For example, the score SC is allocated according to the width of the minimum frequency band including all the frequency bands of the blocks of the distribution. The score attributed to the distribution is then all the higher as the said minimum frequency band is narrow. In addition, the score SC may also depend on the number of collisions between protection bubbles and blocks of the distribution. This score provides an estimate of the quality of adaptation of the block distribution to predetermined constraints. The score assigned to the distribution is even higher than the number of collisions is low. In another example, each distribution is assigned a first score according to the width of the minimum frequency band including all the frequency bands of the blocks of a distribution and a second score according to the number of collisions between bubbles. protection and distribution blocks. In addition, the score or scores also depend on the preferences of some radio systems to use certain frequency bands and not to use other frequency bands. In step E6, the EVA evaluation module compares the SC score assigned to each block distribution to a predetermined threshold SP. If a REP block distribution has an SC score higher than the predetermined threshold SP, block allocation is adopted by the EVA evaluation module to allocate frequency bands to the radiocommunication systems according to the adopted one-stage allocation. E10. If several REP block distributions have a score greater than the predetermined threshold, the adopted block distribution, for example, is the one with the highest score.

If no distribution of REP blocks has a SC score higher than the predetermined threshold SP, the process proceeds to step E7. Alternatively, in the case where multiple scores have been assigned to each split in step E5, the EVA evaluation module adopts the block distribution having all scores above respective predetermined thresholds.

In step E7, the simulation module SIM selects K block distributions to keep having the highest scores among the R block distributions REP for the following steps. For example, K is between R / 2 and R. The unselected distributions are deleted and replaced by certain selected distributions that can be duplicated so as to keep the same number R of distributions. For example, a set of three block distributions contains first, second, and third distributions to which scores in descending order are respectively assigned. The first and second allocations are selected and the third distribution is deleted. The first distribution is then duplicated to obtain another set of three distributions. Duplicating at least the distribution with the highest score ensures retention of this distribution for the next iteration.

In step E8, the SIM simulation module randomly selects at least one REP block distribution among the R distributions from step E7 and at least one BL block of the selected distribution. Several blocks may be selected for example if they have the same spatial coordinates. The SIM module then modifies the position of the selected block or blocks parallel to the frequency axis Of and thus according to the frequency. For example, one or more selected blocks are moved vertically, which amounts to allocating other frequency bands to the radio systems.

In another example, at least one selected block is divided into sub-blocks, which amounts to allocating several disjunct frequency bands to a radio system instead of a single frequency band initially narrower than all frequency bands of the sub-blocks. In step E9, the simulation module SIM selects randomly two distributions of REP blocks among the R distributions from steps E7 and E8, and selects at least one radio system. The blocks associated with each selected radio system are switched between the two distributions selected by the SIM module. The two distributions thus obtained are said to be crossed since each distribution comprises at least one block placed according to the other initial distribution. For example, two distributions are selected. The first distribution comprises three blocks "Al", "A2" and "A3" respectively associated with radio systems "S1", "S2" and "S3". The second distribution comprises three blocks "B1", "B2" and "B3" associated respectively with the 35 radio systems "S1", "S2" and "S3".

If the radiocommunication systems "S1" and "S2" are selected, the two distributions obtained after crossing comprise respectively the three blocks "B1", "B2" and "A3" and the three blocks "Al", 5 "A2. "and" B3 ". Optionally, a block distribution obtained after crossing may comprise overlapping blocks. In this case, this distribution presenting a mutual disturbance between the radiocommunication systems represented by the overlapping blocks and thus having a low score will not be selected in step E7 of the next iteration and will therefore be deleted. At the end of step E9, the process goes back to step E4 for the next iteration. The steps E7 to E9 described above correspond to a particular embodiment of a genetic algorithm which is itself a particular type of optimization algorithm. As a variant, the steps E7 to E9 may be replaced by steps of another optimization algorithm, for example of the "simulated annealing" type.

When the number of iterations iterates reaches a predetermined number of iterations NP and no distribution of blocks REP has a score SC greater than or equal to the predetermined threshold SP at a step E67 intermediate between the steps E6 and E7, the device DAB frequency band allocation requires operators of radio systems to change the spectrum requirements and / or coverage areas of radiocommunication systems.

In this case, the process can go back to step E1 to determine block distributions to be adopted.

In a variant, in step E4, during the iterations succeeding the initial iteration, only the protection bubbles around blocks that have been modified in steps E8 and E9 are determined again.

The invention described herein relates to a method and a device for allocating frequency bands respectively to radio communication systems. According to one implementation, the steps of the method of the invention are determined by the instructions of a computer program incorporated in the frequency band allocation device according to the invention. The program comprises program instructions which, when said program is executed in the device whose operation is then controlled by the execution of the program, carry out the steps of the method according to the invention. Accordingly, the invention also applies to a computer program, in particular a computer program recorded on or in a computer readable recording medium and any data processing device, adapted to implement the invention. This program can use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code such as in a partially compiled form, or in any other form. desirable form for implementing the method according to the invention.

The recording medium may be any entity or device capable of storing the program. For example, the medium may comprise storage means on which the computer program according to the invention, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or a USB key, is stored. or magnetic recording means, for example a floppy disk or a hard disk.

On the other hand, the recording medium may be a transmissible medium such as an electrical or optical signal, which may be conveyed via an electrical or optical cable, by radio or by other means. The program according to the invention can be downloaded in particular on an internet-type network. Alternatively, the recording medium may be an integrated circuit in which the program is incorporated, the circuit being adapted to perform or to be used in carrying out the method according to the invention.

Claims (10)

  1 - Method for allocating frequency bands respectively to radiocommunication systems, characterized in that it comprises: modeling (E2) an allocation of a frequency band to each radiocommunication system by at least one three-dimensional block (BL) according to a frequency bandwidth and a coverage area of the radio system, a determination (E3) of at least one distribution (REP) of the modeled blocks (BL), an allocation (E5 ) a first score at each block distribution based on a minimum frequency band including all the frequency bands of the blocks of the distribution, and an adoption (E 10) of a block distribution having a first higher score at a threshold to allocate frequency bands to the radiocommunication systems according to the distribution adopted.   2 - Process according to claim 1, comprising around model blocks of each block distribution a construction (E4) protection bubbles (BP) in which the radiocommunication systems are able not to undergo mutual interference beyond respective tolerance thresholds, the first score being assigned to each block distribution (REP) in addition to a number of collisions between protection bubbles and blocks of the distribution.   3 - Process according to claim 1, comprising around blocks modeled each block distribution a construction (E4) protection bubbles (BP) in which the radiocommunication systems are able not to undergo mutual interference at above respective tolerance thresholds, a second score being assigned to each block distribution as a function of a number of collisions between protection bubbles and distribution blocks, and a block distribution having first and second scores above respective thresholds being adopted.   4 - Process according to claim 2 or 3, wherein each bubble of protection (BP) is built around a block relative to another block according to the spatial coordinates of the coverage areas associated respectively with the two blocks and propagation characteristics of the radio systems associated with the two blocks. 20   5 - Process according to claim 1 or 2, further comprising, if no block distribution (REP) has a score (SC) greater than the predetermined threshold. A selection (E7) of block distributions (REP) having the highest scores, a replacement (E7) of unselected distributions by selected distributions so as to maintain the same number of distributions, and a random selection (E8) ) at least one block distribution and at least one block (BL) of the selected distribution in order to modify the position of the selected block according to the frequency. 35 2908255 24   The method according to claim 5, further comprising a random selection (E9) of two block distributions (REP) and at least one radio communication system, and an inversion (E9) of the blocks associated with each system of radiocommunications selected between the two selected distributions.   7 - Process according to claim 5 or 6, wherein the construction (E4) of the protection bubbles, the allocation (E5) of a score and the selections (E7, E8, E9) are iterative.   8 - Device (DAB) for allocating frequency bands respectively to radio communication systems, characterized in that it comprises: - means (MOD) for modeling an allocation of a frequency band to each radio system by at least one three-dimensional block (BL) as a function of a frequency bandwidth and a coverage area of the radiocommunication system, -means (MOD) for determining at least one distribution (REP) of the modeled blocks (BL), - means (EVA) for assigning a first score (SC) to each block distribution according to a minimum frequency band including all the frequency bands of the blocks of the distribution, and a means ( EVA) to adopt a block distribution having a first score higher than a threshold in order to allocate frequency bands to the radiocommunication systems according to the distribution adopted. 2908255 25   9 - A device capable computer program (DAB) for allocating frequency bands respectively to radio communication systems, said program being characterized in that it includes instructions which, when the program is loaded and executed in said device, perform the steps of: modeling (E2) an allocation of a frequency band to each radiocommunication system by at least one three-dimensional block (BL) as a function of a frequency bandwidth and a radiocommunication system coverage area, determining (E3) at least one distribution (REP) of the modeled blocks (BL), assigning (E5) a first score to each block distribution according to a frequency band minimum including all the frequency bands of the blocks of the distribution, and adopt (E10) a distribution of blocks having a first score higher than a threshold in order to allocate frequency bands nce to radiocommunication systems according to the distribution adopted.   10 - Recording medium readable by a data processing device for allocating frequency bands respectively to radio communication systems, characterized in that it has recorded a computer program comprising instructions for the execution of the steps to: model (E2) an allocation of a frequency band to each radiocommunication system by at least one three-dimensional block (BL) as a function of a frequency bandwidth and a coverage area of the radiocommunication system Determining (E3) at least one distribution (REP) of the modeled blocks (BL), assigning (E5) a first score to each block distribution according to a minimum frequency band including all the frequency bands of the blocks of the distribution, and adopt (E10) a distribution of blocks having a first score higher than a threshold in order to allocate frequency bands to the radiocommunication systems according to the distribution adopted.